Kooy, F.K., Beeftink, H.H., Eggink, G., Tramper, J., Boeriu, C.G.
Hyaluronan (HA) is a polysaccharide with high-potential medical applications, depending on the chain length and the chain length distribution. Special interest goes to homogeneous HA...
Membrane applications for antibiotics production (2009)
Beeftink, H.H., Tramper, J., Boom, R.M.
In the enzymatic production of antibiotics, membranes can be used for different purposes. Since the enzyme is a cost-determining factor, membrane bioreactors in which the ultrafiltration membrane's...
Drissen, R.E.T., Maas, R.H.W., Tramper, J., Beeftink, H.H.
In ethanol production from cellulose, enzymatic hydrolysis, and fermentative conversion may be performed sequentially (separate hydrolysis and fermentation, SHF) or in a single reaction vessel...
Streefland, M., Herpen, P.F.G., Beuvery, E.C., Tramper, J., ...
A licensed pharmaceutical process is required to be executed within the validated ranges throughout the lifetime of product manufacturing. Changes to the process, especially for processes involving...
Improving the cellular pertussis vaccine: Increased potency and consistency (2008)
Thalen, M., Jansen, D., Beuvery, E.C., ...
Although Europe, Canada and the US have switched from cellular to acellular pertussis vaccines, most developing countries will continue to use the more cost effective cellular vaccine. Consistency of...
Design process of an area-efficient photobioreactor (2008)
Zijffers, J.F., Janssen, M.G.J., Tramper, J., Wijffels, R.H.
This article describes the design process of the Green Solar Collector (GSC), an area-efficient photobioreactor for the outdoor cultivation of microalgae. The overall goal has been to design a system...
Novel applications for microbial transglutaminase beyond food processing (2008)
Transglutaminase (EC 2.3.2.13) initially attracted interest because of its ability to reconstitute small pieces of meat into a `steak¿. The extremely high cost of transglutaminase of animal origin...
Streefland, M., Kint, J., Beuvery, E.C., Tramper, J., ...
Modern (bio)pharmaceutical process development requires thorough investigation of all process parameters that are critical to product quality. The impact of a disturbance of such a parameter during...
Modeling Neisseria meningitidis B metabolism at different specific growth rates (2008)
Baart, G.J.E., Willemsen, M., Khatami, E., Zomer, B., Beuvery, E.C., ...
Neisseria meningitidis is a human pathogen that can infect diverse sites within the human host. The major diseases caused by N. meningitidis are responsible for death and disability, especially in...
Zijffers, J.F., Janssen, M.G.J., Tramper, J., Wijffels, R.H., Salim, S.
The Green Solar Collector (GSC), a photobioreactor designed for area efficient outdoor cultivation of microalgae uses Fresnel lenses and light guides to focus, transport and distribute direct light...
Drissen, R.E.T., Maas, R.H.W., Kabel, M.A., Schols, H.A., Tramper, J., ...
The kinetics of cellulose hydrolysis by commercially available Cellubrix were described mathematically, with Avicel and wheat straw as substrates. It was demonstrated that hydrolysis could be...
Web-based education in bioprocess engineering (2007)
Sessink, O.D.T., Beeftink, H.H., Hartog, R., Tramper, J.
The combination of web technology, knowledge of bioprocess engineering, and theories on learning and instruction might yield innovative learning material for bioprocess engineering. In this article,...
Biocatalysts: Measurement, modelling and design of heterogeneity (2007)
Multiple phenomena are involved in conversions by immobilized biocatalysts. A paradox is identified between analytical desires on one hand and analytical boundary conditions on the other: while the...
Insect cells for human food (2007)
Verkerk, M.C., Tramper, J., Martens, D.E.
There is a need for novel protein sources. Insects are a possible interesting source of protein. They are nutritious in terms of protein (40-75 g/100g dry weight) and minerals. Insect protein is of...
Streefland, M., Happe, R.P., Beuvery, E.C., Tramper, J., ...
Since variation in process time and process output is commonly accepted to be inevitable for biological processes, application of Process Analytical Technologies (PAT) on these processes is...
Dalm, M.C.F., Lamers, P.P., Cuijten, S.M.R., Tjeerdsma, A.M, Tramper, J., ...
For the development of optimal perfusion processes, insight into the effect of feed and bleed rate on cell growth, productivity, and metabolism is essential. In the here presented study the effect of...
Prediction of volumetric productivity of an outdoor photobioreactor (2007)
Bosma, R., Reith, J.H., Tramper, J., Wijffels, R.H.
Volumetric productivity of Monodus subterraneus cultivated in an outdoor pilot-plant bubble column was predicted with a mathematical model. Two border cases to model the photobioreactor were chosen....
Proteus: A lecturer-friendly adaptive tutoring system (2007)
Sessink, O.D.T., Beeftink, H.H., Tramper, J., Hartog, R.J.M.
Effectively targeting a heterogeneous student population is a common challenge in academic courses. Most traditional learning material targets the ¿average student,¿ and is suboptimal for students...
Scale-up for bulk production of vaccine against meningococcal disease (2007)
Baart, G.J.E., Philippi, M., Beuvery, E.C., ...
At the Netherlands Vaccine Institute (NVI) a vaccine against Neisseria meningitidis serogroup B organisms based on different porA subtypes contained in outer membrane vesicles (OMVs) is in advanced...
Jovetic, S., Marinelli, F., Tramper, J.
Immobilized cells of Actinoplanes teichomyceticus ATCC 31121 were used to selectively cleave the acyl group of A40926 yielding the deacylated form of the molecule. The feasibility of this particular...
Rahardjo, Y.S.P., Tramper, J., Rinzema, A.
Solid-state fermentation (SSF) is accompanied inevitably by development of concentration and temperature gradients within the substrate particles and microbial biofilms. These gradients are needed...
Hypothesized kinetic models for describing the growth of globular and encrusting demosponges (2006)
Sipkema, D., Yosef, N.A.M., Adamczewski, M., Osinga, R., Mendola, D., Tramper, J., ...
The marine sponges Dysidea avara and Chondrosia reniformis (globular forms) were cultured in the laboratory on a diet of viable Phaeodactylum tricornutum cells and dissolved nutrients (algae and fish...
Virtual parameter-estimation experiments in Bioprocess-Engineering education (2006)
Sessink, O.D.T., Beeftink, H.H., Hartog, R.J.M., Tramper, J.
Cell growth kinetics and reactor concepts constitute essential knowledge for Bioprocess-Engineering students. Traditional learning of these concepts is supported by lectures, tutorials, and...
Effect of relevant culture parameters on Pertussis toxin expression by Bordetella pertussis (2006)
Thalen, M., Venema, M., Berwald, L., Beuvery, E.C., Martens, D.E., ...
Whooping cough vaccines are produced using different ranges of cultivation conditions and medium compositions, which are known to influence growth rate, virulence factor production and degradation,...
A multicomponent reaction-diffusion model of a heterogeneously distributed immobilized enzyme (2006)
Kallenberg, A.I., Paasman, M.A., Tramper, J., ...
A physical model was derived for the synthesis of the antibiotic cephalexin with an industrial immobilized penicillin G acylase, called Assemblase. In reactions catalyzed by Assemblase, less product...
Hoekema, S., Douma, R.D., Janssen, M.G.J., Tramper, J., Wijffels, R.H.
The main bottleneck in scale-up of phototrophic fermentation is the low efficiency of light energy conversion to the desired product, which is caused by an excessive dissipation of light energy to...
Controlled biosynthesis of glycoseaminoglycan polymers (2006)
Kooy, F.K., Beeftink, H.H., Boeriu, C.G., Eggink, G., Tramper, J.
Kisztelinski, D., Alink, G.M., Bielecki, S., Tramper, J., Martens, D.E.
The aim of the present study is to demonstrate the use of controlled bioreactors for toxicological studies. As a model system the effect of linoleic acid on hybridoma cells is studied in two...
Fed-batch cultivation of Bordetella pertussis: Metabolism and Pertussis Toxin production (2006)
Thalen, M., Venema, M., Dekker, A., Berwald, L., Zomer, B., ...
The production of acellular pertussis in comparison with whole cell pertussis vaccines demands 5-25 times the amount of Bordetella pertussis' virulence factors, such as Pertussis Toxin (PT), to...
Malda, J., Woodfield, T.B.F., Wilson, C., Martens, D.E., Tramper, J., ...
A highly interconnecting and accessible pore network has been suggested as one of a number of prerequisites in the design of scaffolds for tissue engineering. In the present study, two processing...
Rahardjo, Y.S.P., Sie, S., Weber, F.J., Tramper, J., Rinzema, A.
Oxygen transfer in the fungal mat is a major concern in solid-state fermentation (SSF). Oxygen supply into the mycelial layers is hampered by diffusion limitation. For aerobic fungi, like Aspergillus...
Large-scale production of pharmaceuticals by marine sponges: Sea, cell, or synthesis? (2005)
Sipkema, D., Osinga, R., Schatton, W., Mendola, D., Tramper, J., Wijffels, R.H.
Marine sponges are known to produce an overwhelming array of secondary metabolites with pharmaceutical potential. The technical and economical potential of using marine sponges for large-scale...
Rahardjo, Y.S.P., Weber, F.J., Haemers, S., Tramper, J., Rinzema, A.
Aspergillus oryzae is commonly used in solid-state fermentation (SSF) and forms abundant aerial mycelia. Previously, we have shown that aerial mycelia are extremely important for the respiration of...
Field-emission scanning electron microscopy (FESEM) was used in a technical feasibility study to obtain insight into the internal morphology and the intraparticle enzyme distribution of Assemblase®,...
Marine sponges as pharmacy (2005)
Sipkema, D., Franssen, M.C.R., Osinga, R., Tramper, J., Wijffels, R.H.
Marine sponges have been considered as a gold mine during the past 50 years, with respect to the diversity of their secondary metabolites. The biological effects of new metabolites from sponges have...
Rahardjo, Y.S.P., Jolink, F., Haemers, S., Tramper, J., Rinzema, A.
In this paper, the effects of bed porosity, bran and specific surface area on the oxygen uptake rate and ¿-amylase production during growth of Aspergillus oryzae on wheat grain and wheat¿flour...
Enzyme distribution and matrix characteristics in biocatalytic particles (2005)
Boom, R.M., Paasman, M.A., Tramper, J., Beeftink, H.H.
In a study of Assemblase®, an industrial immobilized penicillin-G acylase, various electron microscopic techniques were used to relate intra-particle enzyme heterogeneity with the morphological...
Fluidized-bed and packed-bed characteristics of gel beads (2005)
Tramper, J., Rinzema, A., Beeftink, H.H.
A liquid-fluidized bed or packed bed with gel beads is attractive as an immobilized-cell bioreactor. The performance of such bioreactors is influenced by the physical behavior of these beads. Three...
Dalm, M.C.F., Jansen, M, Keijzer, T.M.P., Oudshoorn, A., Tramper, J., ...
Perfusion systems have the possibility to be operated continuously for several months. It is important that the performance of the cell retention device does not limit the operation time of a...
Malda, J., Woodfield, T.B.F., Wilson, C., Martens, D.E., Tramper, J., ...
A highly interconnecting and accessible pore network has been suggested as one of a number of prerequisites in the design of scaffolds for tissue engineering. In the present study, two processing...
Somsen, D.J., Capelle, A., Tramper, J.
Mass losses during peeling and size sorting of cut strips in French-fries production are heavily influenced by potato size and shape. In this study the number of tubers per kilogram (N) is used as a...
Manufacturing of par-fried french-fries. Part 2: Modelling yield efficiency of peeling (2004)
Somsen, D.J., Capelle, A., Tramper, J.
The paper outlines the yield efficiency of steam peeling. It was proven that peeling potatoes manually with sandpaper results in the lowest possible peel losses. These losses were desired or wanted...
Somsen, D.J., Capelle, A., Tramper, J.
Very little research on the production yield of par-fried French-fries has been reported in the literature. This paper bridges the knowledge gap and outlines the development of a model to predict the...
Malda, J., Martens, D.E., Tramper, J., Riesle, J.
Objective: To determine the effect of dissolved oxygen tension (DO) on the redifferentiation of dedifferentiated adult human nasal septum chondrocytes cultured as pellets. Design: After isolation,...
Malda, J., Rouwkema, J., Martens, D.E., Kooy, F.K., Tramper, J., ...
The supply of oxygen within three-dimensional tissue-engineered (TE) cartilage polymer constructs is mainly by diffusion. Oxygen consumption by cells results in gradients in the oxygen concentration....
Securing web-based exams (2004)
Sessink, O.D.T., Beeftink, H.H., Tramper, J., Hartog, R.J.M.
Learning management systems may offer web-based exam facilities. Such facilities entail a higher risk to exams fraud than traditional paper-based exams. The article discusses security issues with...
Production yield analysis - a new systematic method for improvement of raw material yield (2004)
Somsen, D.J., Capelle, A., Tramper, J.
Production Yield Analysis (PYA) is a structured system approach to optimize the production yield of production processes. The paper outlines the developed method and the 10 basic steps of the PYA....
Production yield analysis in the poultry processing industry (2004)
Somsen, D.J., Capelle, A., Tramper, J.
The paper outlines a case study where the PYA-method (production yield analysis) was implemented at a poultry-slaughtering line, processing 9000 broiler chicks per hour. It was shown that the average...
Effect of oxygen tension on adult articular chondrocytes in microcarrier bioreactor culture (2004)
Malda, J., Meeuwse, P., Grojec, M., Martens, D.E., Tramper, J., ...
Malda, J., Woodfield, T.B.F., Kooy, F.K., Martens, D.E., Tramper, J., ...
Repair of articular cartilage defects using tissue engineered constructs composed of a scaffold and cultured autologous cells holds promise for future treatments. However, nutrient limitation (e.g....
Limitations of membrane cultures as a model solid-state fermentation system (2004)
Rahardjo, Y.S.P., Korona, D., Haemers, S., Weber, F.J., Tramper, J., Rinzema, A.
Aims: To examine the reliability of membrane cultures as a model solid-state fermentation (SSF) system. Methods and Results: In overcultures of Aspergillus oryzae on sterilized wheat flour discs...
Dalm, M.C.F., Cuijten, S.M.R., Tramper, J., Martens, D.E.
For the development of optimal perfusion processes the effect of the feed and bleed rate on cell growth in a perfusion bioreactor was studied. The viable-cell density, viability, growth, death, and...
Janssen, M.G.J., Tramper, J., Mur, L.R., Wijffels, R.H.
Enclosed outdoor photobioreactors need to be developed and designed for large-scale production of phototrophic microorganisms. Both light regime and photosynthetic efficiency were analyzed in...
Primmorphs from seven marine sponges : formation and structure (2003)
Sipkema, D., Tramper, J., Osinga, R., Wijffels, R.H.
Primmorphs were obtained from seven different marine sponges: Stylissa massa, Suberites domuncula, Pseudosuberites aff. andrewsi, Geodia cydonium, Axinella polypoides, Halichondria panicea and...
Optimization of a feed medium for fed-batch culture of insect cells using a genetic algorithm (2003)
Marteijn, R.C.L., Jurrius, O., Dhont, J., Tramper, J., Martens, D.E.
Insect cells have been cultured for over 30 years, but their application is still hampered by low cell densities in batch fermentations and expensive culture media. With respect to the culture...
Barbosa, M.J., Janssen, M.G.J., Ham, N., Tramper, J., Wijffels, R.H.
The slow development of microalgal biotechnology stems from the failure in the design of large-scale photobioreactors where light energy is efficiently utilized. Due to the light gradient inside the...
Author-defined storage in the next generation learning management systems (2003)
Sessink, O.D.T., Beeftink, H.H., Tramper, J., Hartog, R.J.M.
Process intensification: A case for solid-to-solid biocatalysis (2003)
Beeftink, H.H., Michielsen, M.J.F., Ooijkaas, L.P., Tramper, J.
Sponge cell culture? A molecular identification method for sponge cells (2003)
Sipkema, D., Heilig, G.H.J., Akkermans, A.D.L., Osinga, R., Tramper, J., Wijffels, R.H.
Dissociated sponge cells are easily confused with unicellular organisms. This has been an obstacle in the development of sponge-cell lines. We developed a molecular detection method to identify cells...
Tramper, J., Joerink, M., Beeftink, H.H.
The macroscopic kinetic behavior of an industrially employed immobilized penicillin-G acylase, called Assemblase, formed the basis for a discussion on some simple intraparticle biocatalytic model...
What to do in marine biotechnology? (2003)
Tramper, J., Battershill, C., Brandenburg, W.A., Burgess, G., Hill, R., Luiten, E.E.M., ...
During the symposium "Marine Biotechnology: Basics and Applications", held 25 February¿1 March, 2003 in Matalascañas, Spain, a special brainstorm session was organized. Two questions were...
A design environment for downstream processes for Bioprocess-Engineering students (2003)
Vermuë, M.H., Tramper, J., Hartog, R.J.M.
A bioprocess engineer should have at least a set of basic design skills. Bioprocess design is a complex cognitive skill, which should be trained in every year of an academic Bioprocess-Engineering...
Biochemical engineering of solid-state fermentation (2003)
Weber, F.J., Oostra, J., Nagel, F.J.I., Schutyser, M.A.I., Hoogschagen, M.J., Rahardjo, Y.S.P., ...
Marine biotechnology: basics and applications (2003)
Wijffels, R.H., Barbosa, M., Janssen, M., Wessels, H.S., Tramper, J., Vilchez, C., ...
Jovetic, S., Tramper, J., Marinelli, F.
A40926 is a natural glycopeptide antibiotic. It is a precursor of dalbavancin, a semi-synthetic second-generation glycopeptide in clinical development for the treatment of ß-lactam-resistant...
T.R. - Biomolecular Engineering (2003)
Wijffels, R.H., Barbosa, M.J., Janssen, M.G.J., Tramper, J., Vilchez Lobato, C., ...
Expansion of Bovine Chondrocytes on Microcarriers Enhances Redifferentiation (2003)
Malda, J., Blitterswijk Van, C.A., Grojec, M., Martens, D.E., Tramper, J., Riesle, J.
Functional cartilage implants for orthopedic surgery or in vitro tissue evaluation can be created from expanded chondrocytes and biodegradable scaffolds. Expansion of chondrocytes in two-dimensional...
Optimisation of microbial 3-methylcatechol production as affected by culture conditions (2002)
Hüsken, L.E., Beeftink, H.H., Tramper, J., Wery, J.
Pseudomonas putida MC2 can be used to produce catechols. The accumulation, specific and volumetric production rates of 3-methylcatechol from toluene have been studied. Production rates were shown to...
Weber, F.J., Oostra, J., Tramper, J., Rinzema, A.
We have validated our previously described model for scale-up of packed-bed solid-state fermenters (Weber et al., 1999) with experiments in an adiabatic 15-dm3 packed-bed reactor, using the fungi...
In situ product removal during enzymatic cephalexin synthesis by complexation (2002)
Nierstrasz, V.A., Bosma, R., Kemperman, G.J., Strubel, M., Ooijkaas, L.P., ...
In this paper, `complexation' indicates the formation of clathrate type inclusion compounds of cephalexin with naphthalene derivatives. These inclusion compounds readily crystallise in solution,...
Hejazi, M.A., Rocha, J.M.S., Vermuë, M., Tramper, J., Wijffels, R.H.
Simultaneous production and selective extraction of -carotene from living cells of Dunaliella salina in a two-phase system of aqueous and organic phases has been investigated. Solvents with values of...
Integrated reactor concepts for the enzymatic kinetic synthesis of cephalexin (2002)
Nierstrasz, V.A., Bosma, R., Kroon, P.J., Tjeerdsma, P.S., DeVroom, E., ...
Integrated process concepts for enzymatic cephalexin synthesis were investigated by our group, and this article focuses on the integration of reactions and product removal during the reactions. The...
Process design for enzymatic adipyl-7-ADCA hydrolysis (2002)
Nierstrasz, V.A., Bosma, R., Dijkstra, Z.J., Beeftink, H.H., ...
Modelling of the enzymatic kinetically controlled synthesis of cephalexin (2002)
Fretz, C.B., Berendsen, W., Moody, H.M., Roos, E.C., ...
In this study the influence of diffusion limitation on enzymatic kinetically controlled cephalexin synthesis from phenylglycine amide and 7-aminodeacetoxycephalosporinic acid (7-ADCA) was...
Enhancement of enzymatic adipyl-7-ADCA hydrolysis (2002)
Kroon, P.J., Vanderlaan, J.M., Janssen, A.E.M., Tramper, J.
We studied enzymatic adipyl-7-ADCA hydrolysis as a new process for the production of 7-aminodeacetoxycephalosporanic acid (7-ADCA), one of the building blocks for cephalosporin antibiotics like...
Assessment of intraparticle biocatalytic distributions as a tool in rational formulation (2002)
Research has shown that the intraparticle biocatalytic distribution has extensive effects on the properties of various (industrial) biocatalytic particles and their performance in (bio-) chemical...
Nagel, F.J., Tramper, J., Rinzema, A.
Gradients inside substrate particles cannot be prevented in solid-state fermentation. These gradients can have a strong effect on the physiology of the microorganisms but have hitherto received...
Toxicity of terpenes to spores and mycelium op Penicillium digitatum (2002)
Spores, although often considered metabolically inert, catalyze a variety of reactions. The use of spores instead of mycelium for bioconversions has several advantages. In this paper, we describe the...
A novel, inducible, citral lyase purified from spores of Penicillium digitatum (2002)
A novel lyase, combining hydratase and aldolase activity, that converts citral into methylheptenone and acetaldehyde, was purified from spores of Penicillium digitatum. Remarkably, citral lyase...
Rahardjo, Y.S.P., Smit, B.A., Kroon, P.J., Hartmans, S., ...
Alpha-keto acids are key intermediates in the formation of higher alcohols, important flavor components in soy sauce, and produced by the salt-tolerant yeast Zygosaccharomyces rouxii. Unlike most of...
Temperature control in a continuously mixed bioreactor for solid-state fermentation (2001)
Tramper, J., Bakker, M.S.N., Rinzema, A.
A continuously mixed, aseptic paddle mixer was used successfully for solid-state fermentation (SSF) with Aspergillus oryzae on whole wheat kernels. Continuous mixing improved temperature control and...
Model for on-line moisture-content control during solid-state fermentation (2001)
Tramper, J., Bakker, M.S.N., Rinzema, A.
In this study we describe a model that estimates the extracellular (nonfungal) and overall water contents of wheat grains during solid-state fermentation (SSF) with Aspergillus oryzae, using on-line...
Integrated bioproduction and extraction of 3-methylcatechol (2001)
Hüsken, L.E., Dalm, M.C.F., Tramper, J., Wery, J., Beeftink, H.H.
Photosynthetic efficiency of Dunaliella tertiolecta under short light/dark cycles (2001)
Janssen, M., Slenders, P., Tramper, J., Mur, L.R., Wijffels, R.H.
Estimation of steady-state culture characteristics during acceleration-stats with yeasts (2001)
Westerink, B.H., Dijkstal, M.M., Castelein, S.J., Tramper, J., ...
Steady-state culture characteristics are usually determined in chemostat cultivations, which are very time-consuming. In contrast, acceleration-stat (A-stat) cultivations in which the dilution rate...
Intra-particle oxygen diffusion limitation in solid-state fermentation (2001)
Oostra, J., Tramper, J., Rinzema, A.
Oxygen limitation in solid-state fermentation (SSF) has been the topic of modeling studies, but thus far, there has been no experimental elucidation on oxygen-transfer limitation at the particle...
Mohy Eldin, M.S., Janssen, A.E.M., Tramper, J.
The effect of thermodialysis on the enzymatic kinetic synthesis of the antibiotic cephalexin was investigated. As reference points, two existing models for an immobilised enzyme (Assemblase?) and for...
Bonarius, H.P.J., Ozemre, A., Timmerarends, B., Skrabal, P., Tramper, J., Schmid, G., ...
Protein production of mammalian-cell culture is limited due to accumulation of waste products such as lactate, CO2, and ammonia. In this study, the intracellular fluxes of hybridoma cells are...
Solid-to-solid bioconversions: batch or continuous? (2001)
Michielsen, M.J.F., Wijffels, R.H., Tramper, J., Beeftink, H.H.
Application of an accelaration-stat to study insect cell metabolism (2001)
Marteijn, R., Oude Elferink, M., Bron, R., Martens, D., Tramper, J.
Biocatalytic production of semi-synthetic cephalosporis: process technology and integration (2001)
Tramper, J., Beeftink, H.H., Janssen, A.E.M., Ooijkaas, L.P., Strubel, M., ...
Osinga, R., Kleijn, R., Groenendijk, E., Niesink, P., Tramper, J., Wijffels, R.H.
The rate of food particle uptake of the tropical sponge Pseudosuberites aff. andrewsi was studied in relation to particle concentrations and particle size. A range of different concentrations of...
In soy-sauce processes salt-tolerant yeasts are very important for the flavour formation. This flavour formation is, however, slow and poorly understood. In the last decades, a concerted research...
Janssen, M., Tramper, J., Mur, L.R., Snel, J., Wijffels, R.H.
The light regime inside a photobioreactor is characterized by a light gradient with full (sun)light at the light-exposed surface and darkness in the interior of the bioreactor. Consequently,...
Scale-up aspects of photobioreactors : effects of mixing-induced light/dark cycles (2000)
Janssen, M., Baijens, T., Tramper, J., Mur, L.R., Snel, J.F.H., ...
The green micro-algae Chlamydomonas reinhardtii and Dunaliella tertiolecta were cultivated under medium-duration square-wave light/dark cycles with a cycle time of 15 s. These cycles were used to...
Effect of low inoculation density in the scale-up of insect cell cultures (2000)
Marteijn, R.C.L., Martens, D.E., Tramper, J.
The scale-up of insect cell cultures and the production of baculovirus with these cultures is dependent on the inoculation density applied. The effect of applying a low inoculation on the specific...
Growth of Ca-D-malate crystals in a bioreactor (2000)
Michielsen, M.J.F., Frielink, C., Wijffels, R.H., Tramper, J., Beeftink, H.H.
To develop a bioreactor for solid-to-solid conversions, the conversion of solid Ca-maleate to solid Ca-D-malate by permeabilized Pseudomonas pseudoalcaligenes was studied. In a bioreactor seeded with...
Modeling solid-to-solid biocatalysis : Integration of six consecutive steps (2000)
Michielsen, M.J.F., Frielink, C., Wijffels, R.H., Tramper, J., Beeftink, H.H.
A quantitative model for the conversion of a solid-substrate salt to a solid-product salt in a batch bioreactor seeded with product crystals is presented. The overall process consists of six serial...
Mohy Eldin, M.S., Santucci, M., Rossi, S., Tramper, J., Janssen, A.E.M., ...
A new catalytic membrane has been prepared using a nylon membrane grafted by -radiation with methylmethacrylate (MMA) and using hexamethylenediamine (HMDA) as spacer. Penicillin G acylase (PGA) and...
Mohy Eldin, M.S., Bencivenga, U., Rossi, S., Canciglia, P., Caeta, F.S., Tramper, J., ...
Penicillin G acylase (PGA) has been immobilized onto nylon membranes grafted with methylmethacrylate (MMA) or diethyleneglycoldimethacrylate (DGDA) monomers by means of -radiation....
Growth and sporulation stoichiometry and kinetics of coniothyrium minitans on agar media (2000)
Ooijkaas, L.P., Buitelaar, R.M., Tramper, J., Rinzema, A.
Coniothyrium minitans was cultivated on agar media with different concentrations of starch, urea, and trace elements. By means of elemental balances, the stoichiometry of growth and sporulation was...
Equilibrium position, kinetics, and reactor concepts for the adipyl-7-ADCA-hydrolysis process (2000)
Kroon, P.J., Janssen, A.E.M., Tramper, J.
One of the building blocks of cephalosporin antibiotics is 7-amino-deacetoxycephalosporanic acid (7-ADCA). It is currently produced from penicillin G using an elaborate chemical ring-expansion step...
Mulder, A.N.T., Grolle, K.C.F., Engbers, G.H.M., Tramper, J., ...
Entrapment of cells in alginate gel is a widely used mild immobilization procedure. However, alginate gel is not very suitable for use in long-term continuous soy-sauce processes because alginate is...
Smit, B.A., Hartmans, S., Tramper, J., Wijffels, R.H.
To elucidate the growth inhibitory effect of threonine, the regulation of the aspartate-derived amino-acid metabolism in Zygosaccharomyces rouxii, an important yeast for the flavor development in soy...
Effect of temperature of the saccharide composition obtained after alpha-amylosysis of starch (1999)
Marchal, L.M., Goetheer, E., Schimmelpennink, E.B., Bergsma, J., Beeftink, H.H., ...
Stabilization of maleate-hydratase activity of permeabilized Pseudomonas pseudoalcaligenes (1999)
Michielsen, M.J.F., Frielink, C., Meijer, E.A., Wijffels, R.H., Tramper, J., ...
Thermodynamically controlled synthesis of cefamandole (1999)
Nierstrasz, V.A., Bosma, R., Kroon, P.J., Beeftink, H.H., Janssen, A.E.M., ...
Cultivation of marine sponges (1999)
Osinga, R., Tramper, J., Wijffels, R.H.
There is increasing interest in biotechnological production of marine sponge biomass owing to the discovery of many commercially important secondary metabolites in this group of animals. In this...
Modelling fungal solid-state fermentation: the role of inactivation kinetics (1999)
Smits, J.P., Tramper, J., Knol, W.C., Geelhoed, W., Peeters, M., ...
Rational medium design for bordetella pertussis : basic metabolism (1999)
Thalen, M., Jiskoot, W., Zomer, W., Roholl, P., ...
Modelling fungal solid-state fermentation: the role of inactivation kinetics (1999)
Smits, JP, Van Sonsbeek, HM, Tramper, J, Knol, W, Geelhoed, W, Peeters, M, ...
The theoretical mathematical models described in this paper are used to evaluate the effects of fungal biomass inactivation kinetics on a non-isothermal tray solid-state fermentation (SSF). The...
Kinetics of D-malate production by permeabilized Pseudomonas pseudoalcaligenes. (1998)
Michielsen, M.J.F., Meijer, E.A., Wijffels, R.H., Tramper, J., Beeftink, H.H.
Biomass estimation of Coniothyrium minitans in solid-state fermentation. (1998)
Ooijkaas, L.P., Tramper, J., Buitelaar, R.M.
For the estimation of the amount of biomass in solid-state fermentation, various indirect methods are available. The suitability of respiration measurements and the content of various cell components...
Cultivation of marine sponges for metabolite production: applications for biotechnology? (1998)
Osinga, R., Tramper, J., Wijffels, R.H.
The world's oceans harbour a large diversity of living organisms. As tropical rainforests have been searched for natural drugs, these marine organisms are being screened for useful products, and a...
Shear sensitivity of animal cells from a culture-medium perspective. (1998)
Recently, several groups have published data on the shear sensitivity of suspended animal cells and the protective effect of certain polymers. These findings did not, at the time, seem to have great...
In vitro cultivation of four marine sponge species: determination of the nutritional demands. (1998)
Monte Carlo simulation of the alpha-amylolysis of amylopectin potato starch. (1998)
Marcal, L.M., Ulijn, R.V., Zondervan, J., Bergsma, J., Tramper, J.
The influence of temperature on kinetics in solid-state fermentation (1998)
Smits, J.P., Rinzema, A., Tramper, J., Sonsbeek, H.M., Hage, J.C., Kaynak, A., ...
Serial air-lift bioreactors for the approximation of aerated plug flow. (1997)
Bakker, W.A.M., Overdevest, P.E.M., Beeftink, H.H., Tramper, J.
Models for solid-state cultivation of Rhizopus oligosporus. (1997)
Rinzema, A., Oostra, J., Nagel, F.J., Scheepers, B., Nout, M.J.R., ...
The influence of temperature on kinetics in solid-state fermentation. (1997)
Smits, J.P., Rinzema, A., Tramper, J., Hage, J.C., Kaynak, A., ...
On-line estimation of the biomass activity during animal-cell cultivations. (1996)
Dorresteijn, R.C., Harbrink Numan, K., Tramper, J., Beuvery, E.C.
Automation of selective assays for on-line bioprocess monitoring by flowinjection analysis. (1996)
Biselli, M., Wandrey, C., Tramper, J.
On-line analysis of one component in a complex media used for bioprocesses requires the application of selective tests such as enzyme assays. Because these assays are susceptible to interference by...
Metabolic flux analysis of hybridoma cells in different culture media using mass balances. (1996)
Bonarius, H.P.J., Hatzimanikatis, V., Meesters, K.P.H., Schmid, G., Tramper, J.
Guidelines for the characterization of immobilized cells. (1996)
Wijffels, R.H., Buitelaar, R.M., Bucke, C., Poulsen, P.B., Lilly, M.D., Cheetmam, P.S.J., ...
Accurate determination of process variables in a solid-state fermentation system. (1996)
Smits, J.P., Rinzema, A., Tramper, J., Schlösser, E.E., Knol, W.
The design of aqueous two-phase systems (ATPSs) which support the long-term growth of animal cells is described in this paper. It was found that the increase in osmolality caused by the ATPS-forming...
Den Boer, M.M., Vlak, J.M., Tramper, J.
The baculovirus expression system is commonly used in the research and development area and in the production of diagnostics and vaccines. Because the infection of insect-cell cultures with a...
Effects of diffusion limitation on immobilized nitrifying microorganisms at low temperatures. (1995)
Wijffels, R.H., Englund, G., Hunik, J.H., Bakketun, A., Gunther, A., ...
Joksch, B., Gätgens, J., Biselli, M., Tramper, J., ...
A model for solid-state cultivation of Rhizopus oligosporus on soy beans. (1995)
Rinzema, A., Oostra, J., Scheepers, B., Nagel, F.J., Nout, M.J.R., ...
Determination of the respiration quotient for hybridoma cells in bicarbonate buffered medium. (1994)
On-line monitoring of an animal cell culture with multi-channel flow injection analysis. (1994)
Spohn, U., Eberhardt, R., Gaetgens, J., Biselli, M., Wandrey, C., ...
Identification of seven putative origins of Autographa californica MNPV DNA replication. (1993)
Kool, M., Voeten, J.T.M., Goldbach, R.W., Tramper, J., Vlak, J.M.
Vlak, J.M., Voncken, J.W., Kool, M., Usmany, M., ...
Production of recombinant baculoviruses in two stage bioreactor systems. (1991)
Kool, M., Vlak, J.M., ...
Production of (recombinant) baculovirus in two-stage bioreactor systems. (1991)
Kool, M., Vlak, J.M., ...
Production of baculovirus in a continuous insect-cell culture. (1990)
Tramper, J., Kompier, R., Usmany, M., ...
Kool, M., Usmany, M., Tramper, J., ...
Kool, M., Usmany, M., Tramper, J., ...
Continuous production of baculovirus and recombinant derivatives in insect-cell bioreactors. (1990)
Tramper, J., Kool, M., Usmany, M., ...
Tramper, J., Kompier, R., Usmany, M., ...
Kool, M., Usmany, M., Tramper, J., ...
Vlak, J.M., Voncken, J.W., Kool, M., Usmany, M., ...
Vlak, J.M., Voncken, J.W., Kool, M., Usmany, M., ...
Production of baculovirus or recombinant derivatives in continuous insect-cell bioreactors. (1990)
Kool, M., Usmany, M., Vlak, J.M., ...
Kool, M., Usmany, M., Vlak, J.M., ...
Tramper, J., Kompier, R., Usmany, M., ...
Growth of Tagetes sp. in a liquid impelled loopreactor. (1988)
Buitelaar, R.M., Vermue, M.H., Schlattmann, J.E., Tramper, J.
A method for carrying out biotechnological processes by means of multiphase system in a loop reactor, which system comprises an aqueous phase (11) and at least one organic solvent (9, 10) which is...
Stereospecific formation of 1, 2-epoxypropane by alkene-utilizing bacteria (1985)
Carlier, S.J.N., Wistuba, D., Schurig, V., Hartmans, S., ...
Biotechnologie in de Bondsrepubliek (1985)
Verlaan, P., Hamstra, R.S., Hulst, A.C., Brink, L.E.S., Fontijn, M., Tramper, J., ...
The use of immobilized xanthine oxidase and aldehyde oxidase in organic synthesis (1984)
Tramper, J., Naeff, H.S.D., Muller, F., ...
Optimal design for continuous stirred tank reactors in series using Michaelis-Menten kinetics (1982)
Diss. L.H. Wageningen.